ES2274874T3 - THREE-DIMENSIONAL OPTICAL MEMORY. - Google Patents

Abstract

The present invention is directed to a three-dimensional memory apparatus for storing information in a volume comprising of an active medium. The active medium is capable of changing from a first to a second isomeric form as a response to radiation of a light beam having an energy substantially equal to a first threshold energy. The concentration ratio between a first and a second isomeric form in any given volume portion represents a data unit. The active medium in the memory apparatus comprises of diarylalkene derivatives, triene derivatives, polyene derivatives or a mixture thereof. The invention is further directed to means for reading the data units from the isomeric states of the active medium in different portions of said active medium where the two isomeric forms have a substantially different absorption coefficient for absorbing energy of a second threshold energy. Reading may also be carried out by measuring the scattering pattern of the two isomeric forms.

Description

Three-dimensional optical memory.

Field of the Invention

This invention relates to a system of data storage and recovery in three dimensions.

Background of the invention

Reference is made in this description to the following publications:

one)

US 5,592,462

2)

US 5,268,862

The computerized era has increased the need of providing reliable means to store large amounts of data. Currently, the increasing amounts of information are stored in personal and commercial computers, and with the advance of technology, this demand will grow for sure. One approach to satisfy a need like this is to use procedures optics for storing data, since an optical memory enables group information as binary digits at very high density. In addition, stored information could be maintained without damage. for long periods of time, with no apparent loss of information.

US 5,592,462 (Beldock) describes a three-dimensional system to store and retrieve data. In agreement with this publication, incorporated into this document by reference, data is stored and retrieved by irradiating the medium Storage with two rays of interference light. The use of two rays of light allow the definition of the particular part of the volume that is being written or read in each case.

US 5,268,862 (Rentzepis) describes an active medium for use in a system of the type described by Beldock The medium allows two forms of a derivative of the spirobenzopyran to represent the two binary digits. Without However, the memory is kept at a temperature lower than room temperature, typically at -78 ° C. Therefore, write, retrieve written information and read are made at this time temperature. Raising the temperature will erase the information stored, since the active isomer is stable at temperature ambient only for 150 seconds. The maintenance of a Memory like this is expensive and cannot be used commercially. In addition, the reading process is associated with the detection of fluorescence; a process that implies heat, so there is possibility of loss of data stored during reading.

There is, therefore, a need for a memory Low cost optics, stable and effective.

Summary of the invention

According to one aspect, the present invention provides a three-dimensional memory device to store information in a volume comprising an active medium, which is able to switch between a first isomeric form and a second isomeric form and vice versa, in response to a light radiation of an energy substantially equal to a first threshold energy, in which the concentration ratio between the isomeric forms first and second in a given volume part represents a unit of data; said device being characterized by memory because said active medium comprises derivatives diarilalquenos, whose general formula will be described in what follow.

The active medium of the present invention can be embedded in a support matrix, which can be a polymer, and the active medium is chemically bonded thereto. Alternatively, the support matrix may be a wax or a micelle and the active medium is homogeneously distributed in the same.

The information stored by the device of the The present invention is stored as a series of units of fact.

According to another embodiment, the units of data are binary digits, and each part of the active medium included in the volume represents a 0 or a 1. In this case, it establishes a high concentration ratio threshold and a low concentration ratio, and volume parts that have a concentration ratio above the high ratio threshold they represent a digit while the parts that have a concentration ratio below the low ratio threshold They represent the other digit. For example, a part of volume that it has 70% or less of active medium in the first isomeric form, can represent 0, while a volume part that has a 80% or more active medium of the second isomeric form can represent 1.

Alternatively, the data representation is analog, and each concentration ratio represents a unit of predefined data.

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An active medium should be understood as a plurality of molecules or active groups of a confined polymer  within a given volume that is able to change its states between one isomeric form and another.

The first threshold energy corresponds to the energy required to convert photochemically a molecule of the active medium between the first isomeric form and the second.

Diarylalkene derivatives according to the present invention have the general formula Ar_ {1} R_ {1} C = CAr_ {2} R_ {2}, where Ar_ {1} and Ar_ {2}, that could be the same or different, are aryls substituted or not independently substituted, where the substituted groups have a strong absorption in the IR region or can present effective Raman broadcasting and; R_ {1} and R2_, which can be the same or different, they are groups that have strong absorptions in the IR region.

Preferably, the apparatus according to In addition, the invention comprises means for reading the data units of the isomeric forms of the active medium in different parts of the Mentioned active medium.

Preferably, the isomeric form of a part specific to the active medium must be controlled (in the process in writing) and determined (in the reading process) by saying the part at least two rays of light that intersect and interfere in its interior.

According to another of its aspects, the invention provides a method of producing a pattern three-dimensional different absorption coefficients for a light given in a volume comprising the claimed active medium. He active medium comprises diaryl alkene derivatives according to the claim 1, and is capable of being both a first, second or Any other isomeric form. According to this aspect of the invention, the active medium is sensitive to the ray of light having a energy that is substantially equal to a first threshold energy. This method of the invention comprises:

direct a first ray of light, which has a energy different from the one mentioned above, first threshold energy to a selected part of the active medium; Y

direct at least one additional ray of light that has at least one additional energy that is different from the first threshold energy, to the same selected part of the active medium;

in which the combined energy of the first ray of light and at least one additional ray of light is substantially equal to the first threshold energy.

In this process of the invention, the transfer from an isomerically configuration to other configurations of isomeric forms is the result of a multi-button absorption

In accordance with another embodiment of the present invention, the "at least one additional ray of light" is a single additional light ray, and transfer from an isomeric form to the other is the result of a biphoton absorption.

The combined energy can be both the sum as the difference of the energies of the various rays of light directed to the volume of the selected part.

Brief description of the drawings

In order to understand the invention and to see how it can be carried out in practice, now it will be described a preferred embodiment, by means of only one example not limiting, referring to the accompanying drawings in which:

Figures 1A and 1B illustrate, respectively, a U.V. of substituted trans stilbene dough (diester) which shows the formation of the cis isomer, and the spectrum of the isomer formed cis.

Figures 2A and 2B illustrate, respectively, a U.V. of substituted trans stilbene dough (dialcohol) that shows the formation of the cis isomer, and the spectrum of cis isomer formed.

Figure 3 illustrates a UV spectrum of a mass of a substituted trans stilbene (diester) that shows the cis isomer formation.

Figure 4 illustrates a Raman dispersion of the cis isomer

Detailed description of preferred embodiments

According to a preferred embodiment of the In the present invention, the active medium is embedded in a matrix of support. The support matrix can be a polymer, where the active medium is chemically bonded thereto, preferably at through substituents of the aryl groups of the derivatives of diarilalquenos. Alternatively, the active medium may be homogeneously distributed within an inert medium, such as wax or micelles, which contains the medium in the form of cubic phases such as cubeson

According to a preferred embodiment of the present invention, the memory apparatus according to the invention comprises: means to direct the ray of light that has a first energy, different from the first threshold energy, up to one part selected from the active medium, and medium to direct light rays additional that have additional energies, different from the first threshold energy, up to the same selected part of the medium active. The combined energy of the first ray of light and the two additional light rays is substantially equal to the first threshold energy A suitable system for this embodiment is described in reference 2, and in reference 1, for the case in which uses an additional ray of light.

In a preferred embodiment of the invention, Isomeric forms of the active medium have a coefficient of substantially different absorption to absorb energy from a second threshold energy, thus allowing recovery of information in a manner similar to your preferred form of writing, described in the following.

The writing of the information is done normally, according to the present invention, radiating the active medium with light in the visible or UV regions, while the reading typically uses light in the IR region, or it can be detected by measuring the Raman dispersion. Such a reading process to a small energy does not heat the system and does not confuse information stored

The active medium according to the invention, It comprises diarylalkene derivatives of the general formula Ar_ {R} {C} = CAr_ {R2}, the substituents R_ {1} and R 2 of these arylalkene derivatives or the substituents of the aryl rings determine the IR spectrum or dispersion pattern Raman of the two isomeric forms of the active medium. The substituents of the aryl rings and the substituents R 1 and R2 that may be the same or different, are chosen from groups that have strong absorption in the IR region or show Raman dispersion. The IR spectrum of the aryl substituents and of the substituents R 1 and R 2, or their dispersion pattern Raman will be significantly different in each of the ways isomers of the diaryl alkene derivative.

Accordingly, the aryl substituents and R 1 and R 2, which may be similar or different, and preferably are the same, are selected from the group of C 1-8? -Carboxylic acids or of its esters, 2-hydroxyC 1-8 alkyl,
2-fluoroxy C 1-8 alkyl, 2-nitro C 1-8 alkyl, 2-cyano C 1-8 alkyl or a nitro group. Alternatively, one of the R1 or R2 may be as defined above, and the other group may be a polar group, such as a halide or cyano group. More preferably, the aryl substituents and R 1 and R 2 are selected from 2-hydroxyethyl or 2-hydroxypropyl.

The Raman dispersion can be selected by Coherence Anti-Stocks Raman Spectroscopy (CARS), by Raman Induced Kere Effect Spectroscopy (RIKES) or a variation thereof.

The use of such diarylalkane derivatives according to the present claim 1, allows the memory apparatus of the invention to be fully operative at room temperature, due to the great thermal stability of each of its isomeric forms. The two isomeric states of diarylalkene are stable for long periods, and there is no thermally induced spontaneous intermediate conversion from one isomeric to the other. This stability also enables the memory device to be of a type that can be written and read many
times.

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Examples

Example one

Trans -4-bromoestylbeno pure diethylacetate was dissolved in acetonitrile and irradiated with a mercury lamp having an Hg filter. The UV spectrum shown in Figure 1A illustrates the spectrum of the pure trans isomer (indicated with 9401). The cis isomer has a strong absorption at 254 nm and, thus, the resulting spectrum of the mixture formed by trans and cis isomers after 5 minutes of irradiation (indicated with 9601), the resulting spectrum of the mixture formed is also shown. by trans and cis isomers after 8 minutes of irradiation (indicated with 9801) and the resulting spectrum of the mixture formed by trans and cis isomers after 15 minutes of irradiation (indicated with 0301). Figure 1B illustrates the spectrum of cis -4-bromoestylbeno diethylacetate after 18 hours of irradiation.

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Example 2

Pure bis [2-hydroxypropyl] - trans- stilbene was dissolved in acetonitrile and irradiated with a mercury lamp having an Hg filter. The UV spectrum shown in Figure 2A illustrates the trans isomer spectrum (indicated with 4301), the resulting spectrum of the mixture formed by trans and cis isomers (which has a strong absorption at 254 nm) after 2 minutes of irradiation (indicated by 4401), the spectrum resulting from the mixture formed by trans and cis isomers after 6 minutes of irradiation (indicated with 4501). The spectrum of acetonitrile is indicated with 4201. Figure 2B illustrates the spectrum of the cis- stilbene dipropanol as in Figure 2A, however after abstraction of the spectrum of acetonitrile.

Example 3

Trans- stilbene diethylacetate was dissolved in acetonitrile and irradiated with a mercury lamp having an Hg filter. The UV spectrum shown illustrates the spectrum of the pure trans isomer (indicated with 5301), and the resulting spectrum of the cis isomer formed (which has a strong absorption at 254 nm) after 22 hours of irradiation (indicated with 5501) (Figure 3) .

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Example 4

Bis was irradiated [2-hydroxypropyl] -cis-stilbene and the resulting Raman scatter spectrum was illustrated showing the characteristic absorption of hydroxyls (figure 4).

Claims (19)

1. A three-dimensional memory device for storing information in a volume comprising an active medium, which is able to switch between a first and a second way isomer in response to radiation from a ray of light that has a energy substantially equal to a first threshold energy, in which the concentration ratio between a first and a second isomeric form in a given part of volume represents a unit of data; said memory apparatus being characterized in that the said active medium comprises diarylalkane derivatives of the general formula Ar 1 R 1 C = CA 2 R 2, wherein Ar 1 and Ar 2, which they could be the same or different, they are substituted or unsubstituted aryls independently, wherein the substituted groups have a strong absorption in the IR region and; R_ {1} and R2_, which can be the same or different, they are groups that have strong absorption in the region of the IR. 2. The memory apparatus according to claim 1, in which the mentioned data units are digits binary 3. In the memory device, according to the claim 1, wherein said active medium is embedded in a support matrix. 4. The memory apparatus according to claim 3, in which said support matrix is a polymer, and the Said active medium is chemically bonded to a polymer. 5. The memory device according to the claim 3, wherein the support matrix is a wax or a micelle that forms a cubic phase, and the mentioned active medium is homogeneously distributed inside. 6. The memory apparatus according to claim 1, comprising: means to direct a ray of light that has a first energy, different from the mentioned first threshold energy, towards a selected part of the active medium; Y means to direct at least one ray of light additional that has at least one additional energy, also different from the mentioned first threshold energy, towards the mentioned selected part of the active medium; in which the combined energies of the first ray of light and that of the at least one additional ray of light are substantially equal to those of the first threshold energy. 7. The device according to any of the claims 1 to 6 further comprising means for reading the data units of the concentration ratio of the states isomers of the active medium in different parts of said medium active. 8. The device according to any of the claims 1 to 7, in which the two isomeric forms have a  substantially different absorption coefficient to absorb energy of a second threshold energy. 9. The apparatus according to claim 8, in the which the aforementioned absorption coefficient substantially different is in the IR region. 10. The device according to any of the claims 1 to 7, in which the two isomeric forms have a substantially different pattern of energy dispersion incident. 11. The apparatus according to claim 10, in the which the aforementioned substantially different dispersion pattern of incident energy is Raman dispersion. 12. The device according to any of the claims 8 to 9, wherein said means for reading the  data units, comprising means to direct a first ray of light that has a different energy from the second mentioned threshold energy, towards a selected part of the active medium; Y means to direct at least one additional ray of light that has the less an additional energy different from the mentioned second threshold energy, towards the mentioned selected part of the medium active; in which the combined energy of the first ray of light and of the mentioned at least one additional ray of light is substantially equal to said second threshold energy. 13. The memory apparatus according to claim 1, wherein the aryl groups Ar1 and Ar2 are substituted by substituents, and wherein said substituents and the R1 and R2 groups are selected from acids
C 1-8? -carboxylic or esters thereof, 2-hydroxyC 1-8 alkyl, 2-fluoroxyC 1-8 alkyl, 2-nitro C 1-8 alkyl, 2-cyano C 1-8 alkyl or a nitro group. 14. The memory device according to claim 13, wherein the groups R1 and R2 are selected from 2-hydroxyethyl or 2-hydroxypropyl. 15. The memory device according to claims 13 or 14, wherein the substituents of the aryl groups Ar_ {1} and Ar_ {2} are the same, and the groups R 1 and R 2 are the same. 16. The memory device according to claim 1, wherein the aryl groups Ar 1 and Ar 2 are substituted with substituents, and in which the aforementioned substituents are different from the groups R_ {1} and R2_, in which one choose from β-carboxylic acids C 1-8 or its esters, 2-hydroxy C 1-8 alkyl, 2-fluoroxy C 1-8 alkyl, 2-nitro alkyl C 1-8, 2-cyano alkyl C_ {1-8} or a nitro group, and the other is chosen from between a halide or cyano group. 17. The memory device according to claim 16, wherein the groups R1 and R2 are selected from 2-hydroxyethyl or 2-hydroxypropyl 18. A procedure to produce a pattern three-dimensional different absorption coefficient for a threshold energy given in a volume comprising an active medium, the said active medium comprises diarylalkene derivatives of general formula Ar 1 R 1 C = CA 2 R 2, where Ar_ {1} and Ar_ {2}, which could be the same or different, they are substituted or unsubstituted aryls independently, where the substituted groups have a strong absorption in the IR region and; R_ {1} and R2_, which are the same or different, they are groups that have strong absorption in the IR region, and it is capable of being both a first and a second isomeric form, said medium being sensitive to radiation of an energy substantially equal to a first threshold energy; Understanding the procedure: direct a beam of light, which has a first energy different from the mentioned first threshold energy, up to a selected part of the active medium; Y direct at least one different ray of light that has at least one other energy, different from the first mentioned threshold energy, up to the mentioned selected part of the medium active; in which the combined energy of the first ray of light and that of the at least one additional ray of light are substantially equal to the first threshold energy level. 19. A procedure to read data from a three-dimensional pattern of different absorption coefficients for a given threshold energy, comprising: direct a first ray of light that has a first energy, different from the mentioned second threshold energy, towards a selected part of the active medium, comprising diarylalkene derivatives of the general formula Ar_ {R} {C} = CAr {R2}, in which Ar_ {1} and Ar_ {2}, which could be the same or different, they are substituted or unsubstituted aryls independently, where the substituted groups have a strong absorption in the IR region and; direct at least one additional ray of light that It has at least one additional energy, different from the one mentioned threshold energy, towards the mentioned selected part of the medium active; in which the combined energy of the first ray of light and at least one additional ray of light is substantially equal to the threshold energy.